The fraud is that fat and obesity are diseases. They are not. However, it is very much in the interests of the $60 billion weight-loss industry to continue to perpetuate this fraud.

Why are you an authority we should listen to about this?

I am the tour guide to the experts. Over the last 20 years scientists and researchers have conducted hundreds of experiments involving hundreds of thousands of people in order to develop a clear understanding of how the body responds to weight and fitness in terms of morbidity (illness) and mortality.

The results of those experiments directly contradict all the prevailing myths surrounding the so-called “obesity epidemic.” However, these researchers are far more skilled at understanding how the body functions than they are in publicizing their work. As a result, their findings have been overwhelmed by the massive propaganda efforts of the weight-loss industry.

The purpose of The GreatFatFraud was to bring together in one place, in an easily accessible and readable format, all of the research that has been done that exposes the fraud of the “obesity epidemic.”

You make it pretty clear in your book that, with very few exceptions, weight and even BMI is a vanity issue, not a health issue. However, you still talk about dieting and weight loss.

There are really two very valid reasons why people might want to lose weight. The first is that some people are simply not happy with the way that they look when they are heavy. I am not sure I would use the word “vanity” since that tends to have some negative connotations. I would prefer to say that people have every right to make “aesthetic choices” about how they look.

The second reason is that there’s some pretty convincing research showing that people who are heavy experience wage discrimination in the workplace.

For both of those reasons I felt that it was important to discuss weight loss and some of the myths and misconceptions that have surrounded it. The research is fairly conclusive that:

1. Exercise and fitness alone will not result in weight loss for the great majority of people. To lose weight, you still have to diet.

2. Without a continuing fitness regimen, the overwhelming majority of people will, over time, regain whatever weight they have lost.

I've met a number of people who genuinely do have trouble losing weight, even with a fitness-focused plan like the one you suggest. They will lose some weight, but not very much- easily less than ten pounds over the course of a year. Are those the kinds of "results" people should expect?

The research is pretty clear that for most people fitness alone will not result in weight loss. The reason is that the body’s set point recognizes the calorie deficit created by fitness activities and increases one’s hunger level so that they compensate by eating more. So even with a fitness program, most people who want to lose weight will have to consciously diet.

It is also true that some people have enormous difficulty in losing weight. People who find themselves in this situation should seriously consider the precepts of the Health at Every Size movement. Health at Every Size emphasizes body acceptance and intuitive eating among other things. However, even with Health at Every Size, fitness is a critical component of being healthy.

It's very hard to dissociate health from appearance. When we see someone who is "heavy", many automatically assume that they are unhealthy and/or a drain on our public finances.

It is critical here to make a distinction between individuals who are sedentary and individuals who are fit. People who are fit do not have a health problem regardless of their weight. However, high levels of weight when combined with a sedentary lifestyle is a lethal combination.

A thin person who is sedentary has twice the mortality risk of a person who is BMI 30 but fit. A person who is BMI 30 and sedentary has three times the mortality risk of a person who is BMI 30 and fit. And since fitness can be achieved either through exercise or through a 10,000 steps per day walking program, it is a lot easier for most people than losing weight.

And even if someone still holds firmly to the position that fitness is all well and good but you still have to lose weight to be healthy, they’re still going to have to embrace fitness because without fitness, whatever weight someone loses is surely going to be regained.

There's talk about instituting higher insurance premiums and taxes on those with high BMIs. Not coincidentally, we're also talking about taxes on sodas and candy. How do we "decriminalize" the un-thin?

Someone who is heavy and sedentary is most definitely going to have higher health claims costs than someone who is thin and sedentary. But someone who is heavy and fit is going to have substantially lower health claims costs than someone who is thin and sedentary.

It would be massively unfair to penalize someone who is fit but heavy when that person is likely to have half the healthcare claims experience of someone who is thin but sedentary. Corporations who impose or are planning to impose obesity penalties must have a fitness exception. People who are heavy must be given an opportunity to prove that they are fit with a simple treadmill test, and those who are fit must not be penalized.

The $147 billion annual cost figure comes from a study entitled "Annual Medical Spending Attributable to Obesity: Payer and Service-Specific Estimates."The major flaw in this study, like in so many similar studies, is that the population data base being analyzed (in this case the Medical Expenditure Panel Surveys) is not separated into fit and sedentary groupings. If it were, we would undoubtedly see that those who are heavy and fit impose no additional healthcare costs on the system. We would also see that those who are sedentary impose substantial healthcare costs on the system with those costs escalating as weight increases.

Lack of fitness, not obesity, is the primary public health issue for the 21st century.